If semiconductor devices have to process high currents or voltages, high temperatures may occur in the semiconductor body of the semiconductor device and, in the worst case, lead to the destruction of the semiconductor device. In order to prevent overheating of the semiconductor devices, it is known to integrate into the semiconductor body of the semiconductor device a temperature sensor for measuring the temperature prevailing in the semiconductor body. By evaluating a temperature signal supplied by the temperature sensor, it is possible to monitor the temperature within the semiconductor body. If the temperature exceeds a specific threshold value, suitable measures can then be taken for preventing destruction of the semiconductor device. By way of example, it is possible to switch off the semiconductor device when the temperature threshold value is exceeded, cf. e.g. U.S. Pat. No. 6,255,892 B1.
In the case of semiconductor devices with a temperature sensor, the temperature signal evaluation unit is usually integrated into the semiconductor device. In this case the temperature signal evaluation unit can be integrated directly together with the “rest” of the semiconductor device into a common substrate. However, this entails an increased lateral space requirement of the semiconductor device. As an alternative to this, it is possible to integrate the temperature signal evaluation unit into a separate chip, for example the driving chip of the semiconductor device, the separate chip being packed onto the semiconductor device (“chip-on-chip arrangement”), but this requires an increased outlay in the production process, cf. e.g. DE 197 28 281 C1. In both cases it is necessary to reckon with the semiconductor device being made considerably more expensive.
In order to avoid this disadvantage, it is known for the evaluation unit not to be integrated into/onto the semiconductor device, but rather into an external chip situated “outside” the semiconductor device (for example alongside the semiconductor device on a common circuit board), cf. e.g. DE 100 24 516 A1. For this purpose, two electrical connections are usually led out from the semiconductor device and connected to the external control chip. The electrical connections are usually connected to conductor tracks of a circuit board which are in turn connected to the external control chip. In the conductor tracks of the circuit board, however, the temperature signal can easily have interference pulses of other electronic devices superposed on it, which entails a corruption of the temperature signal or makes it completely impossible to measure the temperature. This problem can be combated by choosing the strength of the temperature signal to be sufficiently high.
However, previous temperature sensors only supply temperature signals whose signal strengths are relatively weak. The reason for this is that known temperature sensors measure the leakage current of a pn junction, the current intensity of which is only very small.
For these and other reasons there is a need for the present invention.